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This was pretty cool....

beach

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Oct 20, 2009
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Location
The SoCal Beach
A recent fire in Glendale... office building, 2 story.

Even though sprinkler control valves were shut off, the sprinkler system still controlled the fire!! (perpetrator apparently didn't know to drain the system!!)



The fire was reported at 02:11 hours on January 28, 2013 initially as a fire alarm requiring only a single Engine company to be dispatched. Upon arrival the engine found a two story commercial/retail structure with alarm bells ringing. Upon further investigation, discovered smoke and water coming from the involved unit and requested the balance of a first alarm structure assignment.



Engine found the two front entry doors to the unit unlocked and initially found an activated sprinkler system and 2 chairs smoldering within the front of the office unit. The chairs were removed out through the entry doors to the outside for complete extinguishment. 4 additional and separate fires within the office unit were discovered. These fires occurred upon 2 additional chairs and within two waste cans. Four of the fires within the main office were extinguished by the sprinkler system. Two fires found in office unit #1, one to a chair and one within a waste can, were extinguished by firefighters with a bottle of drinking water found on the desktop in that office.



The involved structure is a 12,095 square foot two story commercial/retail center of Type III (Ordinary) construction. The building is comprised of 1st floor covered parking combined with commercial offices and a second floor comprised of retail space and parking built over the first floor commercial space and parking.



Examination of the Fire Sprinkler system revealed intentional deactivation of the system prior to Fire department arrival. The main inlet valve was found in the closed position. Both isolation valves for the first and second floors were both found in the closed position.

Though the system was shut down in an apparent attempt to prevent the sprinkler system from extinguishing the fire, residual pressure in the system provided enough water for extinguishment.



The office space was approximately 1500 square feet in size. The space was divided into 4 separate office suites and storage room centered around a common office area.



The quick action of the fire sprinkler system was demonstrated by the fact that the fires failed to ignite the large quantity of papers found on every desk in close proximity to each separate fire start.



Damage estimated at $15,000 structure and $65,000 contents.



The origin of these fires was atop the cushions of each chair involved and within the waste cans. A flammable liquid believed to be lighter fluid was used as an accelerant with an undetermined open flame device utilized for ignition. The perpetrator(s) targeted the chairs that utilized polyester upholstery fabric and polyurethane foam cushions to ignite the fires, leaving a leather chair in office #1 untouched.

Polyester and polyurethane foam carry fire well and when impregnated with a flammable liquid burn quickly. The tremendous heat generated immediately by this fuel combination is what led to the rapid activation of the fire sprinkler system.



The multiple fires demonstrated burn patterns on the chairs and within the trash receptacles.



 
WOW, stupid is still alive and well.........sounds like a friction fire........mortgage papes rubbing against the insurance policy.........
 
Beach

Was the automatic sprinkler system control valves monitored electronically? If so did they send the signal into the alarm company? It would be interesting to see the time between valve closure and water flow switch activation.
 
Would a signal go out if the valve was closed.....without a loss of pressure?
Yes, if supervised properly. As soon as the control valve is moved aprox. 1/4 turn in most installations the control valve's electronic supervisory device called a "tamper switch" initiates an electronic signal to the monitoring facility hence the term "tamper switch".

The monitoring facility will have these details available to the AHJ in their event history logs upon request or the monitoring facility will not be code compliant in accordance with NFPA 72.

Beach,

I'll be in San Diego in May for a 101 TC meeting how far are you from there?
 
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Insurance Engineer: It wasn't my city, so I'm not sure what the time lapse was....would be interesting to know, I don't think it would have made much of a difference since it was just a supervisory signal.

FM: I'm about an hour up the coast from SD, let me know the specifics when it get's closer to May!
 
I am missing something here. I don't see how the residual water trapped in the system ext a fire. It must have been a very low btu heat release fire. If the valves are closed, and a fire starts this usually ends with 100 percent damage especially when comb const is involved. Fire loss history has shown this to be the case with most closed valve fires.

Side note: beach, sounds like we are neighbors.
 
This is a decent sized 2 story building with a light hazard occupancy and likely quick response heads. The trapped air in the system would let it act as a pressure tank and the first 30 seconds of water from the heads would likely of knocked down the fire. Remember 13D systems only require a 10 minute water supply.
 
Frank said:
This is a decent sized 2 story building with a light hazard occupancy and likely quick response heads. The trapped air in the system would let it act as a pressure tank and the first 30 seconds of water from the heads would likely of knocked down the fire. Remember 13D systems only require a 10 minute water supply.
Frank,

??? Que ????????

this was an office building in sunny calif, so 99% sure it was a wet system, and being 12000 sq ft and two stories,

so a good amount of water in the system, not a designer, but that and luckily does not sound like a bright arsonist, so not much fire, but enough to activate the heads

The residual pressure and amount of water in the shut off system was enough to activate the flow alarm.

and in most fires only takes one, or maybe a couple more to control the fire.
 
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